1. Field of the Invention
The present invention relates to a mobile communication terminal capable of data transmission using Bluetooth® technology, (hereinafter “Bluetooth”) and in particular, to a method for inputting/outputting voice data during the playback of music data using Bluetooth technology.
2. Description of the Related Art
Generally, short-distance wireless communication technology, such as Bluetooth technology, aims at enabling wireless communication within a short range with little cost. Advantageously, since data can be transmitted/received between terminals or to/from a wireless headset without using cables, the short-distance wireless communication has an increasing field of application. For example, it can be used between a computer and a peripheral device, such as a monitor, a printer, a keyboard, or a wireless headset for wireless connection. The short-distance wireless communication is also applicable to various types of electronic terminals (e.g. PDAs, desktops, FAXs), as well as between a digital multimedia broadcast receiving terminal and a wireless headset.
The Bluetooth generally refers to a protocol for specifying a wireless connection to a variety of terminals and Bluetooth devices at a rate of 1 Mbps by using a frequency in the ISM (Industrial, Scientific, Medical) band of 2.45 GHz. When other Bluetooth devices exist nearby, a mobile communication terminal, i.e. a host device, inspects each Bluetooth device based on a HCI (Host Controller Interface) inquiry. Then, the mobile communication terminal receives information regarding services that an inspected Bluetooth device can provide (e.g. information regarding the profile of the Bluetooth device) based on a HCI response signal from the Bluetooth device.
The profile refers to a driver for driving a Bluetooth device. In particular, the profile corresponds to a set of predetermined commands for driving a Bluetooth device according to a service provided by the Bluetooth device. When the host device inspects a Bluetooth printer and drives it, the host device receives a printer profile from the Bluetooth printer and displays the received profile to the user. If the user instructs via the host device that the Bluetooth printer perform a printing operation, the host device loads the printer profile, which has been received from the Bluetooth printer, and connects to the Bluetooth printer based on the printer profile for the printing operation.
Such profiles typically include a telephone profile, an AG (Audio Gate) profile, an AV (Audio/Video Source) profile, etc. The telephone profile is used to drive a Bluetooth device for providing telephone and wireless communication functions when these functions are to be implemented. The AG profile is used to generate a duplex audio channel between a host device (e.g. mobile communication terminal) and a Bluetooth device so that data is exchanged between them. The AV profile is used to generate a simplex channel, which has a bandwidth greater than that generated by the AG profile, between a host device and a Bluetooth device so as to transmit simplex audio data from the host device to the Bluetooth device.
As described above, the AG profile generates a duplex channel between a Bluetooth device and a host device for real-time duplex data exchange. Thus, if the mobile communication terminal is a portable telephone incorporating a telephone function, and if the Bluetooth device is a headset equipped with both a microphone and a speaker, the AG profile enables the user to make a call by means of the headset.
Unlike the AG profile, the AV profile generates a simplex channel from a host device to a Bluetooth device. Therefore, the bandwidth of a channel generated by the AV profile is twice as large as that of a channel provided by the AG profile. In this case, the channel generated based on the AV profile can transmit data greater than that transmitted via the AG profile channel. Thus, the AV profile is suitable for transmission of high-quality audio data, such as music data.
In the case of a Bluetooth device (e.g. headset), which incorporates both a music data output function and a telephone call function, the device provides the host device with information regarding both the AG and AV profiles as a response to an HCI inquiry of the host device because both profiles are supported. The host device then selects a suitable one from the profiles according to the current operation condition and drives the Bluetooth device. For example, when voice is inputted/outputted during a telephone call, the AG profile is loaded so as to drive the Bluetooth device (headset). When music data (MP3) is played based on the Bluetooth scheme, the AV profile is loaded so as to drive the Bluetooth device (headset).
However, the AG and AV profiles cannot be used inter-changeably because they generate different channels with the Bluetooth device, and different data are transmitted via the channels. For instance, when a Bluetooth device is driven based on the AG profile, a duplex channel can be generated. However, it is impossible to transmit music data to the Bluetooth device via one of the currently generated duplex channel. When the Bluetooth device is driven based on the AV profile, a simple channel is generated through which the user's originating sound cannot be output, thereby making communication impossible.
Therefore, when a Bluetooth device is driven based on the AV profile at the user's request for playback of music data (MP3), the arrival of an incoming call or the user's request for an originating call requires that the connection to the Bluetooth device based on the AV profile be terminated and followed by reconnection to the Bluetooth device based on the AG profile. As such, under the conventional approach, the playback of music data is inevitably interrupted in the case of an incoming or originating call, which results in a user's music listening time being interrupted during a call.